AutoMapperNestedExpressionTest.cs

  public void Main()
  {
      Mapper.Initialize(config => {
          config.CreateMap<ChildModelClass, ChildDataClass>();
          config.CreateMap<ModelClass, DataClass>();
      });

      Expression<Func<DataClass, bool>> expr = d => d.Children.All(c => c.Data == "abc");

      var lambda = (LambdaExpression)Mapper.Map(
          expr, 
          typeof(Expression<Func<DataClass, bool>>), 
          typeof(Expression<Func<ModelClass, bool>>));

      Console.WriteLine(lambda);
  }

  public class ModelClass
  {
      public int ID { get; set; }
      public ChildModelClass[] Children { get; set; }
  }

  public class ChildModelClass
  {
      public string Data { get; set; }
  }

  public class DataClass
  {
      public int ID { get; set; }
      public ChildDataClass[] Children { get; set; }
  }

  public class ChildDataClass
  {
      public string Data { get; set; }
  }